What is the defined minimum thickness for tank walls in API 650?

• A. 1/8 inch (3.17 mm)
• B. 1/4 inch (6.35 mm)
• C. 1/2 inch (12.7 mm)
• D. 3/8 inch (9.53 mm)

Answer: (B)

The defined minimum thickness for tank walls in API 650 is indeed 1/4 inch (6.35 mm). This specification is established to ensure structural integrity and safety of the storage tanks. The specified minimum thickness addresses factors such as the types of materials being stored, environmental conditions, and the potential for corrosion over time. A thickness of 1/4 inch ensures that the tank can withstand various operational pressures and offers sufficient durability while balancing material usage and cost-effectiveness. This standard is applied to reinforced edge plates and components to ensure that they can effectively resist the forces they will encounter during operation, thus safeguarding the stored contents and the surrounding environment.